Climate Change Blog | American Museum of Natural History

He pointed out that the alcohol content of wine used to be about 13 -- 13.5 percent. However, with global warming the alcohol content of has risen to 14 percent.

Sept '08 | Grape growers feeling the freeze

"In San Benito County, we had the same problem as everywhere else in California - terrible weather during the flowering season," said Steve Pessagno, owner of Pessagno Winery.

He noted that from April to May, cold weather and overcast skies created perfect conditions for frost.

"My notebook reads, 'April 12 to 16, coldest string of five days in the last 70 years.'"

The result is demonstrated in Pessagno's Syrah fields, where he obtained one ton of grapes per acre - about a third of a normal year's harvest. He wasn't the only one reporting such a stunning decline, as Rob Leve, a vineyard manager at Gimelli Wineries, gave a similar estimate.